Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society
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Our aim was to determine whether single trial averaging could improve quantification of contact heat evoked potentials measured from fixed position contact heat stimulation. Event-related brain potentials were measured in response to contact heat stimuli applied to the arm and the leg of 10 subjects via a circular thermode, using fixed and varied thermode positions at 41 degrees C and 51 degrees C. Contact heat evoked potentials were successfully recorded from varied position stimulation of the leg at 51 degrees C in 80% of subjects, but from only 60% of subjects using a fixed position. ⋯ The amplitude of the N2-P2 complex and pain intensity ratings were larger for the varied compared with the fixed thermode position and were also larger when stimulating the arm. Automated single trial analysis of the data resulted in larger amplitude of the N2-P2 complex than standard averaging. In conclusion, we have demonstrated that the reduced contact heat evoked potentials amplitude seen for fixed location stimulation can be improved with single-trial averaging.
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J Clin Neurophysiol · Oct 2008
Interobserver agreement in the interpretation of EEG patterns in critically ill adults.
The significance of rhythmic and periodic EEG patterns in critically ill patients is unclear. A universal terminology is needed to facilitate study of these patterns, and consistent observer agreement should be demonstrated in its use. The authors evaluated inter- and intraobserver agreement using the standardized terminology (Hirsch et al., J Clin Neurophysiol 2005;22:128-135) recently proposed by the American Clinical Neurophysiology Society. ⋯ Inter- and intraobserver agreement were consistently lower for optional terms than mandatory terms. Even when standardized terminology is used, the description of rhythmic and periodic EEG patterns varies significantly. Further refinement of the proposed terminology is required to improve inter- and intraobserver agreement.
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J Clin Neurophysiol · Aug 2008
Clinical TrialDetection and treatment of refractory status epilepticus in the intensive care unit.
Status epilepticus (SE) is not rare in critically ill intensive care unit (ICU) patients, but its diagnosis is often delayed or missed, in part because it is mistaken for other causes of altered mental status. Even once diagnosed, SE in the ICU can be refractory to treatment. We sought to determine the causes, clinical features, and difficulties in diagnosis of SE in the ICU, and the effects of antiepileptic drugs (AEDs) on its course. ⋯ ICU patients with altered mental status and EEG evidence of SE often have severe medical and surgical illnesses, refractory SE, and a high mortality. The delay to diagnosis is substantial, but a significant subset of patients improves on AEDs once SE is discovered. This diagnosis should be sought more often in ICU patients with abnormal mental status, especially after clinical seizures or SE without full recovery.
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J Clin Neurophysiol · Aug 2008
Corticospinal facilitation following prolonged proprioceptive stimulation by means of passive wrist movement.
The purpose of this study was to evaluate the delayed effects of repetitive sensory stimulation with passive wrist movement on corticospinal excitability of the forearm and hand musculature. Motor evoked potential responses to single and double pulse transcranial magnetic stimulation were recorded from the flexor carpi radialis, extensor carpi radialis, and the first dorsal interosseous muscles of the right limb. Data were collected before and after a 1 hour session of passive wrist movement (intervention group, n = 11) or after a same period of rest (control group, n = 9). ⋯ Prolonged proprioceptive stimulation with passive wrist movement induces a delayed increase in corticospinal excitability of the forearm muscles. Accordingly, this intervention may promote motor cortical reorganization in the targeted muscles. Results show induced effects from passive movement training that may prove useful for neurorehabilitation therapies.
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J Clin Neurophysiol · Aug 2008
Could electrical needle stimulation reduce diagnostic errors in electromyography?
During the electromyographic examination there is a risk of wrongly inserting the needle in a muscular area contiguous to the muscle of investigation. The objective of the work is to verify the mistakes chance during the needle placement into the muscle target. ⋯ In conclusion, a correct identification of the muscles tested may a useful practice for all patients especially in patients with motor recruitment problems avoiding other serial examinations and reducing patients discomfort. In other hand, this kind of method can be helpful during a training for a neurophysiologist to improve their technical skill.